The invention relates to a method and apparatus to improve approximation of the color of teeth and communication of this color.
The recent development of dental porcelain allows a skilled dental technician to produce a dental prosthesis that closely approximates the natural state, if provided with accurate information of the color of a tooth (or teeth) to be restored. To produce a lifelike dental prosthesis, such as a crown, bridge, etc., dental professionals must communicate among themselves and to patients the often subtle differences in color that are found in human teeth. When formulating the prosthesis, it is important that dentists, dental technicians, and patients refer to the same color.
One of the most commonly used devices to match tooth color has been the dental shade guide. The shade guide, usually made of porcelain or plastic, is commercially available under names such as Vita-Lumin(trademark) (Vita), Bioform(trademark) (Dentsply), and Vitapan 3-D Master(trademark) (Vita).
Such commercial color guides, however, have limited use for several reasons. One reason is that the colors in the guides are not able to match the subtle differences of the colors found in human teeth. Another reason is that the shade guides are grouped in terms of chroma, hue, and value on the basis of the Munsell Chromatic Scale. A dental professional is forced to describe tooth color, which is not a logical system, by a logical system consisting of a letter, a number, or both together. A third reason is that the porcelains or plastics used to make the shade guides are of different quality from the porcelains used by dental professionals in fabricating the prosthesis. The resulting product is frequently of a different color than that of the natural tooth of a patient. Even if the color is closely matched, the subtle differences of individual tooth/teeth color(s) resulting from different values are often ignored or compromised. This diminishes the aesthetic appearance of the prosthesis.
To overcome the problems which accompany the use of commercial shade guides, there have been attempts by dental professionals to produce custom-made shade guides for their own use. Several colored samples of plastic, porcelain, or other materials are usually made to match the various colors of different parts of an individual tooth. This method, however, is very expensive, time-consuming, and the results are not always satisfactory. To remedy the situation, extrinsic modifications of commercial dental color guides also have been attempted. For example, gray plastic or porcelain facets have been made which adapt to an individual shade tab of a shade or color guide to match the value of a tooth, that is, its translucent grayness. This is described by Ubassy in Shape and Color, The Key to Successful Ceramic Restoration, Quintessence Publishing Co., Inc., Chicago (1995). However, more than the difference of value describes the subtlety of colors of human teeth. In addition, the majority of dentists cannot afford to fabricate individual plastic facets or porcelain chips or tabs each time they are needed. There have also been attempts to modify the shade guides by xe2x80x9cstainingxe2x80x9d them. While this may be of some benefit in matching color, it cannot include value.
Other methods to describe the range of colors in human teeth use photographs, slides, or drawings with accompanying description of colors and, in recent years, computer images via the Internet. These methods are limited because the images are influenced by many different factors such as the quality of films, monitors, or cameras. For example, the same image of a tooth viewed on one type of monitor may be different from that when viewed on a different monitor.
Photometers, spectrophotometers, and various digitized and computerized devices have also been introduced to analyze and communicate the color of teeth. Many of these devices are not perfected as yet, and are not practical for the majority of dental professionals because of their cost and/or complexity. Furthermore, even when using these electronic devices, the analyses are still described and communicated in letters, numbers, or both, rather than in color.
There is thus a need for a method to communicate color that is economical, accurate, amenable to use for more than one patient, and easy to use in a dental office.
The invention is directed to a system, and a method of using the system, of a plurality of translucent films having color distributions and/or shades of color found in human teeth, which are used to convey these color distributions among dental professionals and patients. It is understood for this invention that color encompasses both color and the various shades of a particular color. The films may be reversibly self-adhesive for placement or alignment on a template, or on top of another film, until the desired or matching color is achieved. The color to be matched may be that of the entire tooth, or only a section of the tooth. This sequence of films, providing the desired color for each area of the tooth, is conveyed among dental professionals and patients by indicia for the colors. In this way, the system allows the precise, or closely approximated, colors for the areas to be communicated. Subsequently, a dental prosthesis can be made having colors that closely approximate all areas of a patient""s natural tooth, relative to either the tooth or to commercial shade guides.
In one embodiment, the system contains a series of these translucent films in a plurality of the colors found in human teeth. In another embodiment, the colors match those of dental porcelain powders that are used in preparing dental prostheses. The films may be in a variety of sizes and shapes, and may also have divisions corresponding to different parts or areas of the tooth.
The invention will be further appreciated in light of the following drawings and detailed description.